Regenerative braking apparatus for electric vehicle

Abstract

A regenerative braking apparatus has an inverter. The inverter uses the rotational energy of the wheels to let the motor generator generate electric power for the purpose of providing regenerative braking. The regenerative braking apparatus also includes a refrigeration cycle unit and a heating cycle unit. The refrigeration cycle unit compresses a refrigerant with the electric power of the battery in order to heat a heat exchanger. The heating cycle unit is a unit in which a medium heated by the heat exchanger flows to heat the battery. When the battery is in a fully charged state where the battery cannot be charged with regenerative electric power of the motor generator, the regenerative braking apparatus exercises electric power consumption control to force the refrigeration cycle unit and the heating cycle unit to consume the electric power of the battery.

What is claimed is: 
     
       1. A regenerative braking apparatus for an electric vehicle, comprising:
 a motor generator that drives wheels using electric power of a battery; 
 an inverter that drives the motor generator and uses rotational energy of the wheels to let the motor generator generate electric power for a purpose of providing regenerative braking; 
 a refrigeration cycle unit that compresses a refrigerant with the electric power of the battery in order to heat a heat exchanger; 
 a heating cycle unit that is a unit in which a medium heated by the heat exchanger flows to heat the battery; and 
 a control unit that controls the refrigeration cycle unit, the heating cycle unit, and the inverter, wherein 
 the control unit includes an electric power consumption control section which forces the refrigeration cycle unit and the heating cycle unit to consume the electric power of the battery in a situation where the battery cannot be charged with regenerative electric power of the motor generator. 
 
     
     
       2. The regenerative braking apparatus for an electric vehicle according to  claim 1 , wherein
 the electric power consumption control section switches control of the refrigeration cycle unit and of the heating cycle unit between a normal mode and an energy consumption mode in accordance with a charged state of the battery for a purpose of acquiring a braking force derived from regenerative braking, and wherein 
 in the normal mode, the regenerative electric power of the motor generator is used to charge the battery and properly adjust a temperature of the battery, and wherein 
 in the energy consumption mode, the refrigeration cycle unit and the heating cycle unit are forced to consume the electric power of the battery in a predetermined pattern for a purpose of placing the battery in a non-fully charged state where regenerative braking can be applied. 
 
     
     
       3. The regenerative braking apparatus for an electric vehicle according to  claim 1 , wherein
 when the battery cannot be charged with the regenerative electric power of the motor generator, the control unit forces electrical loads other than the refrigeration cycle unit and the heating cycle unit to consume the electric power of the battery in a predetermined pattern. 
 
     
     
       4. The regenerative braking apparatus for an electric vehicle according to  claim 1 , wherein
 a temperature of the medium flowing in the battery is adjusted by the heat exchanger, and wherein 
 the control unit detects a temperature of the battery by using a temperature sensor for measuring the temperature of the medium, and controls the temperature of the medium. 
 
     
     
       5. The regenerative braking apparatus for an electric vehicle according to  claim 1 , wherein
 the control unit sounds or displays a warning to a user when the refrigeration cycle unit, the heating cycle unit, and electrical loads other than the refrigeration cycle unit and the heating cycle unit cannot be forced to sufficiently consume the electric power of the battery. 
 
     
     
       6. The regenerative braking apparatus for an electric vehicle according to  claim 1 , further comprising:
 a cruise control unit that cancels a constant-speed running control when a mechanical brake is operated by a driver of the electric vehicle. 
 
     
     
       7. The regenerative braking apparatus for an electric vehicle according to  claim 1 , wherein
 when a required regenerative braking force is not obtained, the control unit instructs an electric brake control unit to apply a friction brake, the electric brake control unit being an electrical load other than the refrigeration cycle unit and the heating cycle unit.